This invention relates to a battery pack having a thin outline battery fixed in a case.
Battery packs with thin outline batteries are conveniently used by attachment to various portable electrical equipment. In particular, this is the optimum configuration for electrical equipment, such as the portable telephone (cellular telephone), with design requirements for an overall thin outline. Since the overall shape of this type of battery pack is limited by battery thickness, research is being performed to determine how thin the battery can be made. Presently, the polymer battery has been developed as an extremely thin outline battery. The polymer battery is extremely thin overall because aluminum laminate film is used as its exterior. In addition, thin outline lithium ion rechargeable batteries are being developed using steel or aluminum as external cases.
Recently developed thin outline batteries, such as the polymer battery and the lithium ion rechargeable battery, are already designed considerably thin. Further, research is being performed to make these thin outline batteries even thinner without decreasing their charge capacity. Even battery packs which house thin outline batteries are being designed for overall thinness. In particular, battery packs, which attach to electrical equipment requiring a thin shape, such as portable electronics, are required to be designed even thinner. Consequently, design of a thin outline battery pack which does not reduce the charge capacity of the thin outline battery is extremely important, and a battery pack realizing this is in demand.
The present invention was developed with the object of making the battery pack thin by an extremely simple structure without making the thin outline battery itself any thinner. Thus it is a primary object of the present invention to provide a battery pack, which allows battery pack overall thickness to be reduced to the extreme without changing the thickness of the thin outline battery.